Rotary vane pump



June 23, 1964 BIELEFELD 3,138,321

ROTARY VANE PUMP Filed March 22, 1962 ,2 Sheets-Sheet l NVENTOR. Q d 1201/ A B/ZQEFELD P/e/a/e ART BY ,M I 56.5

ATTOE/l/Eff J1me 1964 R. A. BIELEFELD 3,138,321

ROTARY VANE PUMP Filed MaIiOh 22, 1962 2 Sheets-Sheet 2 INVENTOR. A 011A. B/Elf/ELD 147' TOY/V15 V6 United States Patent 3,138,321 ROTARY VANEPUMP Rolf A. Bielefeld, Saint Joseph, MiclL, assignor to GastManufacturing Corporation, Benton Harbor, Mich, a corporation ofMichigan Filed Mar. 22, 1962, Ser. No. 181,618 4 Claims. (Cl. 230152)This invention relates to pumps, and more particularly to rotaryvane-type compressors, and vacuum pumps.

The output and efficiency of a rotary vane-type pump per overall sizeincreases as the rotor hub size decreases, as the number of vanesincreases, and as the length of vanes increases. Long wear and lifecharacteristics are obtained by radially longer vanes. Ordinarily, oneor more of these characteristics is sacrificed in favor of the othersdue to their obviously inconsistent natures. For example, long vanesordinarily require a large rotor hub since the slots, when extended toaccommodate the long vanes, create structural weakness in the hub,especially if a hollow hub is used for maximum cooling as disclosed inapplicants copending application Serial No. 196,267, filed May 21, 1962,and entitled Cooled Rotary Pump. Further, long vanes extending through asmall hub require arranging the slots and vanes at a greater angle tothe radius with the slots thus extending substantially past the centralhub axis. This causes the center of gravity of each vane to besubstantially closer to the hub axis, thereby hindering the centrifugaloutward thrust of the vanes and creating inadequate radial accelerationcharacteristics of the vane. As another example, a large number of vanesordinarily requires short vanes or a large rotor hub since the greaterthe number of slots to accommodate the vanes, the weaker the hubstructure unless it is made substantially larger or the slots are madeshallower. Even when slots are made deeper to accommodate longer vanes,delicate and expensive finishing operations must be performed at thebottom of the slots, thus adding to the expense of the unit.

Another factor ordinarily detracting from top efficiency involves theinsufficient end sealing of vanes on the housing end Walls. Much of theblow-by or leakage occurs along the end walls between the bottom edge ofthe vane and the rotor shaft since the vanes do not extend radiallyinwardly far enough to seal off all of the end wall area.

It is an object of this invention to provide a novel vanetype rotarypump of greatly increased wear life, efficiency and potential output persize of the unit since the structure is inherently capable of employingextra long vanes in a relatively small rotor, and yet in spite of thelong vanes and slots, can accommodate a relatively large number of vanesfor the small rotor size and the greater vane length.

Another object of this invention is to provide a rotary vane-type pumpwherein extra long vanes are accommodated in extended slots where theextension or slot base requires no finishing operations. Further, the extensions, by their configuration or'size create a longer life for thevane due the creation of a distributed wear on the vane sides. Also, thevanes themselves possess a unique configuration providing extra lengthwithout substantially weakening the hub structure, and with a center ofgravity allowing proper centrifugal acceleration to provideuninterrupted sealing on the housing periphery.

FIG. 3.

3,138,321 Patented June 23, 1964 ice Another object of this invention isto provide a novel rotor and vane construction which substantiallyeliminates the usual blow-by at the ends of the housing between thelower edge of the vane and the end shaft.

These and several other objects will be apparent upon studying thefollowing specification in conjunction with the drawings in which:

FIG. 1 is an end view of the novel vane-type pump;

FIG. 2 is an elevational view of the novel rotor hub and end shafts ofthe pump illustrated in FIG. 1;

FIG. 3 is an elevational sectional view of the novel pump taken on planeIIIIII of FIG. 1;

FIG. 4 is an enlarged side view of a vane in the novel rotor slotsshowing the balanced Wear pattern formed thereby;

FIG. 5 is an enlarged view of a vane in a conventional rotor slotshowing the unbalanced wear pattern thereof; and

FIG. 6 is a perspective view of the novel vane used with this pump.

Referring now to the drawings, the novel pump 16 includes a housing 12defining an inner peripheral cylindrical housing wall 14 enclosed by apair of end plates 16 and 18 (FIG. 3). Although the invention isdescribed with respect to a cylindrical housing, it may be generallycylindrical or of some other suitable configuration such as oval shaped.These end plates may be of the simple construction shown or may comprisethe novel construction set forth in my copending application Serial No.196,267, filed May 21, 1962, and entitled Cooled Rotary Pump.Eccentrically mounted within the housing on an axis parallel to that ofthe housing is a rotor hub 20 having integral end shafts 22 and 24 atleast one of which extends through the end plate to permit attachment ofa pulley or coupling (not shown) for driving the pump. The end shaftsare rotatably mounted on bearings 23 and 25 in the end plates. Caps 27and 29 may be used to close the bearings off as desired.

The end shafts and rotor are preferably hollow to define an elongatedpassageway 21 enabling cooling of the apparatus as set forthspecifically in my above identified copending application. Rotor hub 20includes a plurality of generally radially oriented slots 26 extendingthe length of the rotor hub and adapted to receive slidable vanes 28therein. The housing is provided with a conventional inlet port 29 andadjacent end plate 32. The location of the inlet and exhaust ports isnot critical, and may be in the end plates and/ or in the housing.

According to the invention, slots 26 are provided wit a radially inwardextension or cavity well means 40 at the base of each slot 26. Eachcavity well means in cludes at least cavities 42 and 44 adjacent the endwalls 16 and 18, and preferably includes a plurality of spaced cavitiesover the breadth of the hub slot 26 from end to end of the rotor hub asillustrated at 42, 43 and 44 in Intermediate the cavities arestrengthening ribs or webs which provide the necessary structuralrigidity and strength to the hub even though the slots are extended aconsiderable amount, and even though a hollow hub and end shafts areused. The slot extensions protrude radially within the cylindricalperiphery of the end shafts and thus within the circular conjunction 66of the end shafts with the rotor hub as seen in FIG. 1. Preferably,

3 the end cavities extend a small amount into the end shaft itself as at68 and 70.

In forming the novel rotor, the entire hub and end shafts are cast asone integral unit with the slots and slot extensions or cavity meansbeing cored out according to conventional casting processes. Theextensions or cavity means are formed with a width substantially greaterthan the adjacent portions of the slots. Thus, the side walls and bottomsurface of the added cavities need not be finished by machining sincethe vanes do not contact these surfaces. Shoulders 70 and 72 are formedbetween the narrower and wider slot portions. The shoulder is in slidingcontact along a substantial portion of the side surface adjacent theinner edge of the vane during operation (as described hereinafter) toproduce a balanced wear pattern on both ends of the vane.

Extra long vanes are used in combination with the special rotor hub thelength L of each vane (FIG. 6) is the dimension from the inner edge tothe outer edge. The breadth B (FIG. 6) is the dimension from one lateraledge to the opposite lateral edge. The width W is the smallest dimensionfrom face to face across the thickness of the vane. The same terminologyapplies to corresponding slot dimensions. Each vane includes a pluralityof spaced projecting fingers 60 interfitting with the hub slot extensioncavities, and a plurality of intermediate recesses 62 interfitting withthe hub strengthening ribs 50. In splite of the extra length of thevanes, the center of gravity is close enough to the outer edge to effectproper centrifugal vane acceleration and thereby forestall hanging up ofthe vanes in the depressed position. This is achieved both by thecut-away recesses 62 in the vanes and the diagonal beveled portions at88. The cavities may also be shaped with a taper 90 to match thediagonal inner vane edge, thereby further strengthening the hubstructure.

Operation During operation of the pump, acting either as a compressor ora vacuum pump, air is introduced through inlet port 29 and is compressedby the rotating hub and vanes as the space between the hub and thehousing inner peripheral wall becomes smaller. The vanes are thusdepressed gradually into the slots. When the vane becomes completelydepressed like vane 28' in FIG. 1, the inner edge thereof with itsprojections extend into the cavities within the imaginary cylindricalextension of the end shafts into the rotor hub. Thus, the side edges 80(FIG. 3) of the vanes contact the inner walls 82 of the end plates overthe entire distance between the outer peripheral housing wall 14 and thecylindrical periphery of the shafts 22 and 24. Thus, this entire area issubstantially sealed against blow-by.

The extra length of the vane provides longer life since the notchedinner edge is capable of supporting the worn vanes to supply much morewearing surface at the outer edge.

Also, long effective life is achieved by a novel balanced wear pattern(FIG. 4) caused by the extra wide extension or cavity means. As eachvane rotates, it tends to bear against one outer edge of the slot 92 andagainst the novel shoulder 70. As the vane slides backwardly andforwardly over these edges, wear occurs over a large area of the vane oneach end like that indicated in phantom at 96 and 98. Thus, the wear oneach end is spread over an area of the vane rather than beingconcentrated. According to the prior art as illustrated in FIG. 5, edgewear on the outer end 91 is over an area but wear on the inner end ofthe vane is along the very edge 93 rather than on a large side area ofthe vanes, thereby resulting in localized wear which creates greatersloppiness and faster deterioration of the vane. may occur to those inthe art upon studying the principles of the invention taught, withoutdeparting from the inventive concept. Such modifications are deemedVarious other advantages and slightly modifications 4 to be part of thisinvention which is to be limited only by the scope of the appendedclaims and the reasonably equivalent structures thereto.

I claim:

1. In a rotary vane pump, the combination of a housing; a rotor hubeccentrically located in said housing; said housing including endplates; end shafts extending from both ends of said rotor hub into saidend plates; at least more than four elongated slots in said rotor hubfor receiving slidable vanes; said slots extending perpendicular to adiameter of said hub and extending beyond said diameter; the innermostportions of said slots including a plurality of longitudinally spacedrecesses separated by a plurality of strengthening ribs formed integralwith the central portion of said rotor hub; and a plurality of vanes insaid slots having cooperating projections to fit into said recesses andcooperating cut outs to receive said ribs to enable vanes with said cutouts to be accommodated in said slots without detrimentally weakeningsaid hub.

2. In a rotary vane pump, the combination of: a housing, a rotor hubeccentrically mounted in said housing; said housing including end plateshaving faces closely adjacent the ends of said rotor to form a sealagainst excessive gaseous flow around the ends of revolving vanes;integral end shafts extending from both ends of said rotor hub into saidend plates and through at least one end plate; a plurality of elongatedslots in said rotor hub for receiving elongated slidable vanes; cavitywell means at the base of each of said slots extending radially inwardlypast the end shaft peripheries and extending the breadth of said hubfrom one end plate to the other end plate; said cavity well meansincluding a plurality of wells separated by strengthening webs formedintegrally with the central portion of said rotor hub; and sliding vanesin said slots extending from one end plate to the other end plate toform a seal on the end plates against excessive gaseous leakage bycontacting said end plates; said sliding vanes including cut outportions for receiving said strengthening webs; at least thelongitudinal end portions of each of said vanes being longer than therespective slot to extend into said well means when depressed into saidslots during operation and thereby seal off the end wall area betweenthe end shafts and the bottom end portions of said vanes tosubstantially lessen leakage of gases thereby under high compressionconditions.

3. A rotary pump comprising: a housing including a peripheral inner walland two end walls; a rotor hub eccentrically and rotatably mounted insaid housing and having its end surfaces closely adjacent said housingend walls; circular end shafts extending from said rotor through atleast one of said end walls; a plurality of elongated vane-receivingslots in said hub extending the breadth of said hub from one housing endwall to the other housing end wall; each of said slots having aplurality of longitudinally spaced recesses extending radially inwardlyinto said hub past the periphery of said shafts and separated bystrengthening ribs formed integral with the central portion of said hub;and a vane in each of said slots contacting and forming a seal againstsaid housing end walls by extending the breadth of said slots from onehousing end wall to the other housing end wall and said sliding vanesincluding cut out portions for receiving said strengthening webs,portions of said vanes adjacent said end plates extending into certainof said recesses when depressed during operation thereby to seal an areaon the end walls to a radial depth to substantially eliminate gaseousleakage beneath the ends of the vanes and adjacent the end shafts underhigh compression conditions; and spaced portions of the inner edges ofsaid vanes being removed in a manner to leave intermediate portions ofordinary vane width to shift the center of gravity thereof radiallyoutwardly for proper centrifugal sealing action between said vanes andsaid peripheral inner wall.

4. In a rotary vane pump, the combination of a housing; a rotor hubeccentrically located in said housing; said housing including endplates; end shafts extending from both ends of said rotor hub into saidend plates; at least more than four elongated slots in said rotor hubfor receiving slidable vanes; said slots extending perpendicular to adiameter of said hub and extending beyond said diameter; the innermostportions of said slots including a plurality of longitudinally spacedrecesses including at least recesses at the ends of said rotor, andintermediate strengthening ribs; said recesses having a Width greaterthan that of adjacent slot portions to remove the necessity of surfacefinishing operations in said recesses; and a plurality of vanes in saidslots having cooperating projections to fit into said recesses andcooperating cut-outs to receive said ribs to enable vanes with saidcut-outs to be accommodated in said slots and contacting said end platesto obtain optimum end sealing between the vanes and the end plateswithout detrimentally weakening said 6 .r hub and without shifting thecenter of gravity of said vanes an excessive amount to hamper radialacceleration of the vanes.

References Cited in the file of this patent UNITED STATES PATENTS708,684 Wepplo Sept. 9, 1902 1,658,524 Gurley Feb. 7, 1928 2,015,501Sorge Sept. 24, 1935 2,423,639 Czarnecki July 8, 1947 2,448,108 McCalebAug. 31, 1948 2,662,483 Smith Dec. 15, 1953 2,731,920 Scognamillo Jan.24, 1956 2,818,025 Hein Dec. 31, 1957 2,949,081 Deschamps Aug. 16, 19602,952,215 Deschamps Sept. 13, 1960 3,000,324 Rosaen Sept. 19, 19613,021,790 Brunson Feb. 20, 1962 3,031,975 Erdman Mar. 1, 1962

1. IN A ROTARY VANE PUMP, THE COMBINATION OF A HOUSING; A ROTOR HUBECCENTRICALLY LOCATED IN SAID HOUSING; SAID HOUSING INCLUDING ENDPLATES; END SHAFTS EXTENDING FROM BOTH ENDS OF SAID ROTOR HUB INTO SAIDEND PLATES; AT LEAST MORE THAN FOUR ELONGATED SLOTS IN SAID ROTOR HUBFOR RECEIVING SLIDABLE VANES; SAID SLOTS EXTENDING PERPENDICULAR TO ADIAMETER OF SAID HUB AND EXTENDING BEYOND SAID DIAMETER; THE INNERMOSTPORTIONS OF SAID SLOTS INCLUDING A PLURALITY OF LONGITUDINALLY SPACEDRECESSES SEPARATED BY A PLURALITY OF STRENGTHENING RIBS FORMED INTEGRALWITH THE CENTRAL PORTION OF SAID ROTOR HUB; AND A PLURALITY OF VANES INSAID SLOTS HAVING COOPERATING PROJECTIONS TO FIT INTO SAID RECESSES ANDCOOPERATING CUT OUTS TO RECEIVE SAID RIBS TO ENABLE VANES WITH SAID CUTOUTS TO BE ACCOMMODATED IN SAID SLOTS WITHOUT DETRIMENTALLY WEAKENINGSAID HUB.